Devices and methods for guidewire extension in spinal surgery

ABSTRACT

A guidewire system for spine surgeries includes a first guidewire portion having an elongate first guidewire body with a distal end and a proximal end. A threaded male fastener at the distal end of the first guidewire body is configured to fasten to a vertebra of a spine of a subject and a threaded female coupler at the proximal end of the first guidewire body defines a threaded opening. The guidewire system includes a second guidewire portion having an elongate second guidewire body with a distal end and a proximal end. A threaded male coupler at the distal end of the second guidewire body is configured to thread into the threaded female coupler of the first guidewire portion to fasten the second guidewire portion to the first guidewire portion to form an elongate guidewire.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication No. 62/545,574, filed on Aug. 15, 2017, the entirety ofwhich is hereby incorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to spinal surgery guidewiresand methods.

BACKGROUND

Spinal surgeries, including sacroiliac joint fusion, often utilizeguidewires that anchor into the spine to guide surgical instruments,etc. to the correct position. Generally, prior art guidewires are onlyone piece with a non-adjustable length.

SUMMARY

In one aspect, a guidewire system for spine surgeries generallycomprises a first guidewire portion including an elongate firstguidewire body having a distal end, a proximal end, and a longitudinalaxis extending between the distal and proximal ends. A threaded malefastener at the distal end of the first guidewire body extends distallytherefrom. The threaded male fastener is configured to fasten to avertebra of a spine of a subject. A threaded female coupler extendsdistally from the proximal end of the first guidewire body and defines athreaded opening. A second guidewire portion includes an elongate secondguidewire body having a distal end, a proximal end, and a longitudinalaxis extending between the distal and proximal ends. A threaded malecoupler at the distal end of the second guidewire body extends distallytherefrom. The threaded male coupler is adapted to thread into thethreaded female coupler of the first guidewire portion to fasten thesecond guidewire portion to the first guidewire portion to form anelongate guidewire.

In another aspect, a guidewire for spinal surgeries generally comprisesan elongate guidewire body including a distal end, a proximal end, and alongitudinal axis extending between the distal and proximal ends. Athreaded male fastener at the distal end of the guidewire body extendsdistally therefrom. The threaded male fastener is adapted to thread intoa vertebra of a spine of a subject. A threaded female coupler extendsdistally from the proximal end of the guidewire body.

In yet another aspect, a surgical method generally comprises threading athreaded male fastener of a first guidewire portion into a vertebra of aspine of a subject to anchor the first guidewire portion to the spine.The threaded male fastener is at a distal end of an elongate firstguidewire body of the first guidewire portion. A threaded male couplerof a second guidewire portion is threaded into a threaded female couplerat a proximal end of the first guidewire portion to attach the secondguidewire portion to the first guidewire portion, thereby creating anelongate guidewire.

Other aspects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation of a human spine;

FIG. 2A is an elevation of a first guidewire portion of a guidewiresystem;

FIG. 2B is an elevation of a second guidewire portion of the guidewiresystem;

FIG. 3 is an enlarged view of a section of the first guidewire portionas indicated in FIG. 2A;

FIG. 4 is an enlarged fragmentary section taken through line 4-4 in FIG.2A;

FIG. 5 is an enlarged view of a section of the second guidewire portionas indicated in FIG. 2B;

FIG. 6 is a front elevation of a first guidewire portion threading intothe sacrum; and

FIG. 7 is a front elevation of a second guidewire portion threading intoa first guidewire portion that is threaded into the sacrum.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

Referring to FIG. 1, a spine is generally indicated at SP. Near thebottom of the spine, the sacrum is indicated at S. The presentapplication discloses methods and associated devices applicable tomultiple spinal surgeries and includes sacroiliac joint SIJ fusion as anon-limiting example. The devices and methods disclosed are well-suitedto SIJ fusion, but it will be apparent to one of skill in the art thatother applications are possible without departing from the scope of thepresent disclosure.

Referring to FIGS. 2A and 2B, a guidewire system for a spinal surgery isgenerally indicated at 10. A first guidewire portion 12, which can alsobe considered a guidewire, is configured to be anchored to a vertebra ofthe spine, and a second guidewire portion 42, which can also beconsidered a guidewire extender, is configured to thread into the firstguidewire portion 12 to provide a guidewire of a length appropriate forthe surgery. More specifically, the first guidewire portion 12 comprisesa threaded female coupler, generally indicated at 26, and the secondguidewire portion 42 comprises a threaded male coupler, generallyindicated at 50, which threads into (e.g., connects to) the threadedfemale coupler 26. This arrangement allows a surgeon to use the firstguidewire portion 12 without regard to whether it is long enough. If thefirst guidewire portion 12 is not long enough, then the second guidewireportion 42 is used to extend the length of the guidewire system 10. Thesecond guidewire portion 42 does not need to be used if the length ofthe first guidewire portion 12 is suitable. Examples of factors thataffect how much guidewire length is necessary include the size of asubject undergoing surgery and the type of surgery. In addition, it maybe beneficial to initially use the first guidewire portion 12 forinstalling in the spine SP since the first guidewire portion will beshorter, less likely to bend, and easier to control than a guidewirehaving an increased length, such as the combination of the first andsecond guidewire portions 10. However, the shorter guidewire (e.g., thefirst guide portion 12) may only have a short exposed length extendingoutside the patient's body, making it difficult to pass instrumentationover it. Often times when switching from a drill to a screw driver, forexample, the guidewire can unintendedly travel, particularly when notexposed behind a working instrument. Because the sacral foramina haveexiting nerves, it is dangerous to have traveling guidewires in SIJfusion (as well as percutaneous pedicle screws in the lumbar spine foranterior vascular risks). The guidewire extender (e.g., second guidewireportion) 42 allows for a shorter initial guidewire portion 12 to besecured into desired anatomic location and then the guidewire system 10can be extended when needed. This provides a control point when removingand inserting other instrumentation and helps prevent unintended guidewire travel to neural of vascular structures.

The first guidewire portion 12 comprises an elongate first guidewirebody 14 having a distal end 16, a proximal end 18, and a longitudinalaxis LA, extending between the distal and proximal ends. The firstguidewire potion 12 further comprises a threaded male fastener,generally indicated at 20, which extends distally from the distal end 16of the first guidewire body 14 along the longitudinal axis LA. Thethreaded female coupler 26 extends distally along the longitudinal axisLA from the proximal end 18 of the first guidewire body 14. In anembodiment, the first guidewire portion 12 has a length extendingbetween the proximal and distal ends 18, 16 of, for example, about 300mm, or from about 200 mm and about 400 mm, although other lengths arewithin the scope of the present disclosure.

Referring to FIG. 3, the threaded male fastener 20 comprises anon-threaded section 24 and a threaded section 22. While the threadedmale fastener 20 can be any of various types of fasteners in otherembodiments, in the illustrated embodiment it is a self-tapping screw.The non-threaded section 24 extends distally along the longitudinal axisLA from a location at or near the distal end 16 of the first guidewirebody 14 toward the threaded section 22. A bevel 25 located at the distalend 16 of the first guidewire body 14 can be included adjacent to or aspart of the threaded male fastener 20. The threaded section 22 of thethreaded male fastener 20 extends distally along the longitudinal axisLA to a free end that defines a point. In other embodiments the free endmay define a shape other than a point or the threaded section 22 may notextend to the free end of the first guidewire portion 12. Preferably,the threaded male fastener 20 is configured to thread directly into(e.g., attach to) the vertebra, but as explained below, the threadedmale fastener can also be configured to attach to a separate spinalanchor. Other embodiments are possible; for example, certain embodimentshave male fasteners 20 without a non-threaded section 24. Someembodiments, including some embodiments configured for use with a spinalanchor, include male fasteners 20 that form a bolt, non-self-tappingscrew, or other type of fastener. In yet other embodiments, the malefastener 20 may not be threaded and may be configured to be secure tothe sacrum S or other vertebra in other ways.

Referring to FIG. 4, the threaded female coupler 26 comprises an annularwall 28 and a distal wall 30. In the illustrated embodiment, the distalwall 30 has a generally conical shape, but in other embodiments it canbe other shapes such as a flat and circular. The annular wall 28 definesa threaded opening (e.g., male fastener receiving space) 32 and anentrance 34 at the proximal end 18 into the threaded opening 32. Whilethe illustrated embodiment has cylindrical guidewire portions 12, 42with a threaded opening 32 (e.g., tapped hole) along the longitudinalaxes LA of the guidewire portions, other shapes for the threaded femalecoupler 26 are also contemplated within the scope of the disclosure.

The annular wall 28 comprises a shank section 36, a threaded section 38,and a clearance section 40. The shank section 36 is generally smooth andextends from a location at or near the proximal end 18 of the firstguidewire body 14 distally along the longitudinal axis LA towards thethreaded section 38. The shank section 36 may include or be adjacent toa bevel 39 at the proximal end 18 of the first guidewire body 14. Thethreaded section 38 extends distally from the shank section 36 towardsthe clearance section 40, and is configured to engage the threaded malecoupler 50 of the second guidewire portion 42. The clearance section 40is generally smooth and extends distally from the threaded section 38towards the distal wall 30. In other embodiments, by way of example, thethreaded section 38 could extend further along the longitudinal axis ineither the proximal or distal direction or both directions, eliminatingthe clearance section 40, the shank section 36, or both. A taper couldalso be used in place of the bevel 39, or the bevel 39 could simply beomitted, among other changes that could be made without departing fromthe scope of the present disclosure.

The distal wall 30 defines the distal boundary of the threaded opening32. In a preferred embodiment, the free end of the threaded male coupler50 is spaced a distance along the longitudinal axis LA from the distalwall 30 even when the threaded male coupler 50 is fully threaded withthe female threaded coupler 26. In this way, guidewire systems 10 withairtight threads provide room for any air trapped by the threads. Otherembodiments are also possible within the scope of the disclosure.

Referring again to FIG. 2B, the second guidewire portion 42 comprises anelongate second guidewire body 44 having distal and proximal ends 46, 48and a longitudinal axis LA extending between the distal and proximalends. The second guidewire portion 42 further comprises a threaded malecoupler, generally indicated at 50, extending distally from the distalend 46 of the second guidewire body 44 along the longitudinal axis LA. Asecond threaded female coupler 52 extends distally along thelongitudinal axis LA from the proximal end 48 of the second guidewirebody 44, and defines a second threaded opening 62. The second threadedfemale coupler 52 and second threaded opening 62 are the same asthreaded female coupler 26 and opening 32, respectively. Otherembodiments may vary significantly from this exemplary illustration. Forexample, the second threaded female coupler 52 may be entirely absent insome embodiments. In an embodiment the second guidewire portion 42 has alength extending between the proximal and distal ends 48, 46 of, forexample, about 300 mm, or from about 200 mm to about 400 mm, althoughother lengths are within the scope of the present disclosure.

Referring to FIG. 5, the threaded male coupler 50 of the secondguidewire portion 42 is configured to thread into the threaded femalecoupler 26 of the first guidewire portion 12. The threaded male coupler50 comprises a shank section 54, a threaded section 56, and a roundedend (e.g., free end) 58. The lengths of the threaded section 56 and theshank section 54 of the threaded male coupler 50 generally correspond tothe lengths of the threaded section 38 and the shank section 36 of thethreaded female coupler 26, respectively. The shank section 54 isgenerally smooth and extends distally along the longitudinal axis LAfrom a location at or near the distal end 46 of the second guidewirebody 44 towards the threaded section 56. The shank section 54 mayinclude or be adjacent to a bevel 60 at the distal end 46 of the secondguidewire body 44. The threaded section 56 extends distally, and isconfigured to engage the threaded female coupler 26 of the firstguidewire body 14, specifically the threaded section 38. The rounded end58 extends distally from a location near the end of the threaded section56 and is generally smooth. Preferably, the rounded end 58 has a lengthalong the longitudinal axis LA of less than the length along thelongitudinal axis LA of the clearance section 40 of the threaded femalefastener 26. In other words, in the preferred embodiment, the length ofthe threaded opening 32 of the threaded female fastener 26 between theproximal end 18 and the distal wall 30 is greater than the length of thethreaded male coupler 50 between the distal end 46 and the rounded end(e.g., free end) 58 so that the male coupler can be completely insertedinto the female coupler with room to spare. In one embodiment, therounded end 58 has a sufficient length, such as a length equal to orgreater than the length of the threaded section 56, so that the roundedend 46 helps facilitate the connection (e.g., insertion) of the malecoupler 50 into the female coupler 26 (e.g., the rounded end helps guidethe male coupler 50 into the female coupler). In other embodiments, byway of example, the threaded section 56 could extend further along thelongitudinal axis LA in either the proximal or distal direction or bothdirections, eliminating the rounded end 58, the shank section 54, orboth. The rounded end 58 could be shaped differently, for example, flat,among other changes that could be made without departing from the scopeof the present disclosure. In one embodiment, the distal wall 30 of thefemale coupler 26 is shaped to correspond to the shape of the end 58 ofthe male coupler 50.

The configuration presented of the threaded female coupler 26 and thethreaded male coupler 50 allows the first guidewire portion 12 and thesecond guidewire portion 42 to thread (e.g., connect) together. In apreferred embodiment, the connection also allows the distal end 46 ofthe second guidewire body 44 to mate (e.g., engage) with the proximalend 18 of the first guidewire body 14 when the threads are fullyengaged. Preferably, the threads are designed so the guidewire systemcan be threaded until the guidewire portions mate and so that when theguidewire portions mate, the threads are tight. Preferably, the firstguidewire portion 12 and the second guidewire portion 42 are also ofequal outer diameters, for example about 0.125 inches across or between0.075 and 0.25 inches, so that the guidewire system 10 forms an almostsmooth outer surface of the guidewire even at the point where theguidewire portions meet.

The first guidewire portion 12 and the second guidewire portion 42 areidentical in some embodiments. In such an embodiment, the threaded malecoupler 50 and threaded male fastener 20 are preferably designed inaccordance with the description of the threaded male fastener 20. Thethreaded female couplers 26, 52 on both guidewire portions 12, 42 areconfigured to threadably receive the interchangeable threaded malefastener 20 or threaded male coupler 50. Such an embodiment is generallyeasier and cheaper to manufacture because only one unique part or nounique part is manufactured. Moreover, the threads in the threadedsections 22, 38, 46 of the first and second guidewire portions 12, 42can be right-handed threads (e.g., standard threads) or left-handedthreads (e.g., reversed-threads).

In another aspect, a surgical method comprises anchoring a firstguidewire portion to a vertebra or sacrum of the spine and threading asecond guidewire portion into the first guidewire portion. In someembodiments, the first guidewire portion is configured to be usablewithout the second guidewire portion, and the second guidewire portionis only used when needed or convenient, for example when operating on alarger patient.

FIGS. 6 and 7 illustrate a surgical method as applied to sacroiliacjoint fusion (SIJ fusion) using a first guidewire portion 12 and asecond guidewire portion 42. A sacroiliac joint SIJ and surroundingbones are shown in FIGS. 6 and 7. In SIJ fusion, an ilium IL of asubject is mechanically fastened to a sacrum S of the subject to forcethem to grow together. The sacroiliac joint SIJ is a large joint thatforms where the sacrum S and the ilium IL meet. In cases where SIJfusion is found appropriate, preferably a subject lays down on anoperating table, is sedated, and an operating corridor is made, allaccording to methods known in the art. In the embodiment illustrated,the guidewire system 10 disclosed in FIGS. 2-5 and the accompanyingdescription is used.

Referring to FIG. 6, a first guidewire portion 12 of the guidewiresystem 10 is then, after the operating corridor is made, anchored to thesacrum S of the spine of the subject. The guidewire portion 12 isgenerally positioned near the middle of the operative corridor.Preferably the first guidewire portion 12 threads directly into thesacrum S. Alternatively, a separate spinal anchor (not shown) may beused, in which case the spinal anchor attaches at or near the sacrum Sand the first guidewire portion 12 attaches to the spinal anchor.

Referring to FIG. 7, the second guidewire portion 42 is then threadedinto the first guidewire portion 12 to form an elongate guidewire system10 of an appropriate length. In some methods, the surgeon will firstevaluate whether an extra length is needed. When the guidewire system 10is installed, any necessary surgical instruments and tools can be guidedprecisely to the right point. As will be apparent to one skilled in theart, the same method and similar methods can be practiced in a varietyof spinal surgeries without departing from the scope of the disclosure.Among other differences, applying such a method to other surgeriesvaries from the previous description in that a different vertebra may beused. For example, the second guidewire portion 42 may be used forpercutaneous pedicle screw placement and/or imaged guided placement ofpedicle screws.

In all embodiments, the guidewire portions 12, 42 are preferably madefrom a surgical-grade material that is easy to sterilize. By way ofnon-limiting example, stainless steel or titanium can be used. In otherembodiments, the guidewire portions 12, 42 are sealed in sterilecontainers and intended for single use only.

In other embodiments, more than two guidewire portions 12, 42 form theextended guidewire system 10. For example, additional (e.g., third,fourth, fifth, etc.) guidewire extenders (e.g., second guidewireportions) 42 may successively added in series to the first guidewireextender connected to the first guidewire portion 12 to create anelongate guidewire system 10 of any desired length.

When introducing elements of the present invention or the preferredembodiment(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

As various changes could be made in the above apparatuses, systems, andmethods without departing from the scope of the invention, it isintended that all matter contained in the above description and shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:
 1. A guidewire system for spine surgeriescomprising: a first guidewire portion including an elongate firstguidewire body having a distal end, a proximal end, and a longitudinalaxis extending between the distal and proximal ends, a threaded malefastener at the distal end of the first guidewire body and extendingdistally therefrom, the threaded male fastener being configured tofasten to a vertebra of a spine of a subject, and a threaded femalecoupler extending distally from the proximal end of the first guidewirebody and defining a threaded opening; and a second guidewire portionincluding an elongate second guidewire body having a distal end, aproximal end, and a longitudinal axis extending between the distal andproximal ends, and a threaded male coupler at the distal end of thesecond guidewire body and extending distally therefrom, the threadedmale coupler being adapted to thread into the threaded female coupler ofthe first guidewire portion to fasten the second guidewire portion tothe first guidewire portion to form an elongate guidewire.
 2. Theguidewire system of claim 1 wherein the first guidewire portion isidentical to the second guidewire portion.
 3. The guidewire system ofclaim 1 wherein the male fastener is adapted to fasten to the vertebraindirectly through use of a spinal anchor.
 4. The guidewire system ofclaim 1 wherein a threaded section of the threaded female coupler isspaced at a distance along the longitudinal axis from the proximal endof the first guidewire body, and the threaded male coupler is insertablealong said distance without threading.
 5. The guidewire system of claim1 wherein the proximal end of the first guidewire portion is configuredto mate with the distal end of the second guidewire portion when thethreaded male coupler is threaded into the threaded female coupler. 6.The guidewire system of claim 5 wherein the male coupler of the secondguidewire portion has a rounded distal end.
 7. The guidewire system ofclaim 5, the threaded female coupler of the first guidewire portionfurther comprising: a wall defining a threaded hole; a threaded sectionwherein the wall is threaded; and a shank section wherein the wall isnot threaded, the shank section located between the threaded section andthe proximal end of the first guidewire body.
 8. The guidewire system ofclaim 1 wherein the threaded male fastener is configured to thread intoa vertebra of a spine of a subject.
 9. The guidewire system of claim 8wherein the first guidewire portion and the second guidewire portion areidentical.
 10. The guidewire system of claim 8, the threaded femalecoupler of the first guidewire further comprising a wall defining thethreaded opening, the wall having: a threaded section; and a shanksection between the proximal end of the first guidewire portion and thethreaded section; and the threaded male coupler of the second guidewireportion further comprising: a threaded section; and a non-threaded shanksection between the threaded section and the distal end of the secondguidewire portion, the shank section adapted to fit in the shank sectionof the female threaded coupler when the threaded male coupler isthreaded into the threaded female.
 11. The guidewire system of claim 8,further comprising a third guidewire portion, the third guidewireportion comprising an elongate third guidewire body having a distal end,a proximal end, and a longitudinal axis extending between the distal andproximal ends, and a threaded male coupler at the distal end of thethird guidewire body and extending distally therefrom, the threaded malecoupler of the third guidewire portion being adapted to thread into thethreaded female coupler of the first guidewire portion to fasten thethird guidewire portion to the first guidewire portion to form anelongate guidewire; and wherein the second guidewire portion has alength and the third guidewire portion has a length different from thelength of the second guidewire portion.
 12. A guidewire for spinalsurgeries comprising: an elongate guidewire body including a distal end,a proximal end, and a longitudinal axis extending between the distal andproximal ends; a threaded male fastener at the distal end of theguidewire body and extending distally therefrom, the threaded malefastener being adapted to thread into a vertebra of a spine of asubject, and a threaded female coupler extending distally from theproximal end of the guidewire body.
 13. A combination including theguidewire of claim 12 and a guidewire extender, the guidewire extendercomprising: an elongate extender body including a distal end, a proximalend, and a longitudinal axis extending between the distal and proximalends; and a threaded male coupler extending along the longitudinal axisfrom the distal end, the threaded male coupler configured to thread intothe threaded female coupler of the guidewire.
 14. The combination ofclaim 13, wherein the proximal end of the guidewire and the distal endof the guidewire extender mate when the guidewire extender is fullythreaded into the guidewire.
 15. The combination of claim 13, whereinthe guidewire extender is a first guidewire extender, and wherein thecombination further comprises a second guidewire extender, the secondguidewire extender comprising: a second elongate extender body includinga distal end, a proximal end, and a longitudinal axis extending betweenthe distal and proximal ends; and a second threaded male couplerextending along the longitudinal axis from the distal end, the secondthreaded male coupler configured to thread into the threaded femalecoupler of the guidewire; wherein the first guidewire extender has alength and the second guidewire extender has a length different from thelength of the first guidewire extender.
 16. A surgical methodcomprising: threading a threaded male fastener of a first guidewireportion into a vertebrae of a spine of a subject to anchor the firstguidewire portion to the spine, wherein the threaded male fastener is ata distal end of an elongate first guidewire body of the first guidewireportion; threading a threaded male coupler of a second guidewire portioninto a threaded female coupler at a proximal end of the first guidewireportion to attach the second guidewire portion to the first guidewireportion, thereby creating an elongate guidewire.
 17. The surgical methodof claim 16 wherein the step of threading the male coupler into thethreaded female coupler comprises threading the male coupler into thethreaded female coupler until the proximal end of the first guidewireportion mates with the distal end of the second guidewire portion. 18.The surgical method of claim 16 wherein the vertebra is the sacrum. 19.The surgical method of claim 16 wherein the first guidewire portion isthreaded directly into the vertebra.
 20. The surgical method of claim 16wherein the step of threading the threaded male faster of the firstguidewire portion into the vertebra comprises threading the threadedmale fastener into a separate anchor piece and anchoring the anchorpiece to the vertebra.